Cysteine

Mechanism :

Cysteine can usually be synthesized within the human body provided there is enough methionine. However, it is an essential amino acid in infants, neonates, the elderly and conditions where there is protein loss such as malabsorption syndrome. Cysteine is a sulphur containing amino acid which when supplemented, aids in fulfilling nutritional requirements and acts as an anti-oxidant by forming glutathione. In patient or neonates who cannot synthesize adequote quontites of endogenouses Cysteine  due to deficient activity of  enzyme cystothionase act as a preassure or in formation of cysteine.

Indication :

• To fulfill nutritional requirements of neonates requiring total parenteral nutrition
• To fulfill nutritional requirements of pediatric patients with severe hepatic disease with deranged enzymatic processes requiring total parenteral nutrition
• Can also be added to amino acid solutions to provide a more complete amino acid profile for protein synthesis
• Extensive burns, where there is an increase in need for proteins.

Contraindications :

Renal dysfunction:

Aluminium is an additive, which can accumulate to toxic doses if the kidney function is impaired leading to neonatal bone, CNS defects and can also lead to azotemia. Hence, lower doses must be used. clinically evaluate and closely monitor renal functions in neonate.

Hepatic dysfunction: 

Hyperammonemia which can lead to mental retardation is associated with use of cysteine in hepatic insufficiency. Hence, lower doses must be used.  clinically evaluate and closely monitor liver functions in neonate.

Dosing :

Adverse Effect :

Pyrexia, nausea, infusion site redness, phlebitis, warmth, thrombosis, generalized flushing.

Interaction :

No known interactions. However, some of it’s additives may interact with other drugs, hence, caution must be used.

Lactation :

There is no available data about the presence of cysteine in human or animal milk and it’s effects on lactation or on breastfed infants. However, it is not expected to be hazardous to the breastfed infant. Prior to administration, one must consider the risks of neonatal cysteine exposure, risk of an untreated condition and benefits of breast-feeding.

Hepatic Dose :

Prior to administration of the drug, clinically evaluate and closely monitor liver function tests like bilirubin, AST, ALT, etc.

Pregnanacy :

Data is not sufficient to measure the risk of birth defects, stillbirth and adverse maternal and fetal outcome with the use of the drug. There is no data from animal reproduction studies